1. Statement of the Technical Field
The inventive arrangements relate to robotics and more particularly to robotic methods and systems for grasping objects.
2. Description of the Related Art
Systems involving robotics and telematics frequently include some means by which a machine can grasp and manipulate objects. Systems for grasping well known objects, or a limited number of object types, present a relatively straightforward design problem because a gripper design can be selected that is well suited to the particular task. Such grasping problems can be addressed with relative ease using conventional structured grasping methods. For example, grasping devices in such scenarios can have two or three solid fingers with simple geometry (flat surfaces). Alternatively, the fingers used in such simple grasping devices can have a geometry that includes a customized surface which is particularly effective for grasping objects having a specific geometry.
The design problem can be more complex with regard to devices which are expected to grasp a wider variety of objects of arbitrary shape. The absence of a priori knowledge regarding the type of object, variation in object type, variable/unknown object location and/or variable object pose can present a difficult design challenge. This difficulty is compounded by the additional need for a grasping device to have a design which is simple, robust and tolerant of poor or inaccurate sensor information. Grasping devices have been developed which include fully or partially articulated fingers that are able to grasp a wider variety of objects having different shapes. However, these types of grasping devices often require complex grasp planning and a good knowledge of the grasped object. Also, grasping devices with fully or partially articulated fingers can often require many actuators. The complexity and number of actuators tend to make such devices expensive and prone to mechanical failure.
Soft grippers are also known in the art. Soft grippers have a gripping pad formed of a pliable outer membrane which encloses a granulated media material. The gripping pad is pushed onto an object to be grasped and a vacuum is then applied to the interior of the pad. This causes the granulated media within the pad to rigidly conform the pad to the object, thereby gripping same. Soft grippers have some advantages insofar as they are able to conform to a relatively wide variety of arbitrarily shaped objects. However, they require the gripping pad to be pushed onto objects with significant force. Also, the pliable outer membrane is prone to being punctured or wearing out.